IPv4Scanner guides in Guides. All posts »
2026-09-29 · IPV4 Scanner · 5 min read
Which AI bots to allow and which to block, the exact robots.txt tokens for GPTBot, ClaudeBot and the rest, and why blocking the wrong one removes you from AI search.
2026-09-28 · IPV4 Scanner · 5 min read
Anyone can put GPTBot in a user-agent string. Here's how to check an AI crawler is genuine using published IP ranges and forward-confirmed reverse DNS.
2026-09-27 · IPV4 Scanner · 4 min read
What open, closed and filtered ports actually mean, how to check a port from outside your network, and which ports you never want exposed.
2026-09-26 · IPV4 Scanner · 5 min read
What each common DNS record type does, when to use a CNAME versus an A record, and the mistakes that quietly break a domain.
2026-09-25 · IPV4 Scanner · 4 min read
What ping actually measures, what counts as good for gaming and video calls, and why a low ping matters more than a big download number.
2026-09-24 · IPV4 Scanner · 4 min read
What each line of a traceroute means, why gaps and high hops usually aren't the problem, and how to actually tell where a slow connection breaks.
2026-09-23 · IPV4 Scanner · 4 min read
The real reasons legitimate email lands in spam, from authentication to reputation to blacklists, and a practical order to fix them in.
2026-09-22 · IPV4 Scanner · 5 min read
What SPF, DKIM and DMARC actually do, how the three fit together to stop spoofing, and the order to set them up without breaking your own mail.
2026-09-21 · IPV4 Scanner · 4 min read
Where IP location data comes from, how accurate it actually is by country and connection type, and why it puts some people in the middle of a field.
2026-09-21 · IPV4 Scanner · 5 min read
How DNS blacklists work, why your address ended up on one, and the realistic steps to get removed and stay off.
2026-09-20 · IPV4 Scanner · 4 min read
What the slash in 192.168.1.0/24 means, how to work out network and broadcast addresses, and how to split a network without the maths hurting.
2026-09-19 · IPV4 Scanner · 4 min read
How much bandwidth each activity actually needs, why upload and latency matter more than the headline number, and how to stop overpaying.
2026-09-19 · IPV4 Scanner · 5 min read
Why two speed tests minutes apart disagree, which variables actually matter, and how to run a test you can draw conclusions from.
2026-09-18 · IPV4 Scanner · 4 min read
How to read a WHOIS record, which dates and statuses actually matter, and why most contact details are now redacted.
2026-09-18 · IPV4 Scanner · 4 min read
What domain privacy actually hides, what GDPR already redacts for free, and when paying for privacy protection is worth it.
2026-09-17 · IPV4 Scanner · 4 min read
Find your router's IP address on Windows, macOS, Linux, iPhone and Android, plus what to do when the usual addresses don't work.
2026-09-16 · IPV4 Scanner · 5 min read
What a VPN, a proxy and Tor actually do to your traffic, what each one hides and from whom, and which is the right tool for the problem you have.
2026-09-16 · IPV4 Scanner · 4 min read
The real difference between static and dynamic IP addresses, when paying for a static one is worth it, and the workarounds that make it unnecessary.
2026-09-15 · IPV4 Scanner · 5 min read
What an IP address actually is, why yours changes, the difference between public and private addresses, and what a website can really tell about you from it.
2026-09-15 · IPV4 Scanner · 5 min read
Why IPv6 exists, how it differs from IPv4 beyond address length, why adoption took decades, and what it means for you in practice.
2026-09-14 · IPV4 Scanner · 6 min read
Why DNS changes don't appear instantly, what TTL actually controls, and how to check propagation from around the world without waiting 48 hours.